Mikrotik, speed when forwarding VPN traffic to a specific ip in test 0, what's wrong?

Question

VPN

In general, the essence of the problem: I have Internet access via an LTE USB modem and a PPTP client on Mikrotik, traffic from a certain local ip is marked and routed through this PPTP connection, but in the end, for some reason, the download speed in speedtest corresponds to the channel, and the upload speed is 0 and pings are normal, but pages load slowly, and if you connect to the same vpn from a PC, then everything is fine, I tried changing the protocol to L2TP, with and without encryption, it does not help. PPTP in the "WAN" list as well as the LTE modem and in the FireWall the "masquerade" action. I myself recently began to study this, rummaged through the entire Internet, I did not find an answer. Help me solve the problem? maybe you didn't check the box somewhere?

Answer 1

To start with zero information, so that you can be helped with such questions, the picture should be as complete as possible, dump the firewall rules, nat and everything else that you did.
The most banal version of the curvature of your settings I can give you how to check.
1) Make a backup
2) pull out the wired Internet cable
3) reset all settings
4) configure only lte as a normal Internet without any tinkering in other settings
5) see that absolutely everything works
6) raise vpn
7) again you will observe that everything is fine
8 !) Here you hang problems either in the firewall or in traffic marking.
Well, a snag for thought, since the Internet still works, it should not ambiguously hint that the problem is somewhere in an obvious place and very likely hints that something establishes a connection from you to the server and drives traffic in both directions, but absolutely cannot do it in the opposite direction direction.